Topband
[Top] [All Lists]

Topband: Switching in Extra Antenna Length

To: <topband@contesting.com>
Subject: Topband: Switching in Extra Antenna Length
From: df2py@t-online.de (DF2PY)
Date: Wed, 3 Jul 2002 07:46:14 +0200
Hello Bill & reflectees
the problems of switching at the high impedance tip of a quarter wave vertical 
can easily be overcome.
I would suggest a trap ! Like on other frequencies it would serve to decouple 
the lower frequecy part of the antenna from the higher frequency resonator.
It will be a bit bulky, but by far less troublesome as a relay up in the rough 
winterly environment.
And there is another physical problem that has not been looked into :
The vacuum relay yields an external spacing of maximum 2 inches.That distance 
is 
too close to avoid coupling- which is very high at that impedance.
I tested that by using a wire to fix a dipole- using 4 inch insulators- and it 
was impossible to get resonance ! i had to use Nylon cord to get it right. That 
proves the problems with the high impedance points.
Thats the best advice i can give from my experience with antennas.
73 de wolf    df2py


<Prev in Thread] Current Thread [Next in Thread>